The present invention relates to a layered product in a package ready for non-touch application which product comprises a cover layer to which an adhesive layer is unreleasably fastened and a release layer which is releasably fastened to the adhesive layer. The package comprises a top layer and a bottom layer where the top layer is next to the cover layer and the bottom layer is next to the adhesive layer and the top and bottom layers are releasably sealed to each other isolating the adhesive layer from the surroundings.
It is desirable to be able to apply an adhesive product such as a dressing without touching the adhesive layer in order to avoid reducing the adhesiveness of the product. Also it is desirable to be able to apply a sterile dressing to a patient""s skin without touching the surface of the dressing that is to come into contact with the skin in order to avoid introducing bacteria to the wound.
The prior art discloses several methods for facilitating handling of wound dressings and one method is described in U.S. Pat. No. 5,106,629 (NDM Acquisition Corp.). The product of this patent is constituted of three layers: a dimensionally stable backing layer, a transparent adhesive layer and a release layer. When applying the dressing, the release layer is removed by using an extending tab attached thereto, to expose the adhesive layer. The remaining layers of the wound dressing are then applied to the wound site with the adhesive layer directly contacting the wound. Once these layers are in place, the dimensionally stable backing member is removed, preferably using an extending tab attached hereto.
Another method is described in WO 97/43991 (Coloplast A/S). The object of this invention is to ensure easy handling of a wound dressing which comprises a main part and a handle part. The main part comprises a carrier layer, an adhesive layer and a release liner. The handle part comprises one or more tab members designed for use as a xe2x80x9cnon-touchxe2x80x9d grip when applying the dressing to the skin. The tab member and the main part of the dressing do not have all layers in common, reducing the force which needs to be applied in order to remove the tab member after applying the dressing.
These two documents explain how to handle the product without touching the adhesive during application but they do not combine discrete packaging of the products with non-touch application of the products.
A third productxe2x80x94a medical adhesive compositexe2x80x94is described in WO 98/00080 (Minnesota Mining and Manufacturing Company). This medical adhesive composite, e.g. a dressing, is combined with a package, the packaged product comprises a top sheet of packaging material, a carrier material, a conformable backing material, a pressure sensitive adhesive and a bottom sheet of packaging material with a release surface. The carrier material is preferably substantially more rigid than the backing material in order to prevent the backing from wrinkling or folding onto itself in whole or in part during application of the dressing. The carrier material is capable of being attached to the backing by any suitable method, such as heat sealing, adhesives, mechanical bonds, wax coatings etc. The bond is secure, yet releasable, i.e. the carrier and backing can be separated without destroying the integrity of the backing or the bond between the adhesive on the backing and the skin of a patient. In addition the bond between the carrier and the backing should be stronger than the bond between the adhesive on the bottom face of the backing and the release liner or surface of the packaging. Adhering the medical adhesive composites directly to the bottom sheet of the packaging material rather than including a separate release liner on the product simplifies the process of dispensing the medical adhesive composites. The bond strength between the release surface and the bottom sheet is greater than the bond strength between the release surface and the adhesive on the bottom face of the backing.
This document shows how it is possible to include packaging of the product into a single process but the used process is rather complicated and the packaged product may be difficult to apply.
In EP Patent Application No. 938 882 is disclosed a release paper in the form of a sheet with several discrete plasters. The plasters comprise an adhesive layer, covered on one side with the release paper and on the other side with a top film. A pouch covering the wound area maybe located between the adhesive and the release paper. The plasters are separated from each other by a perforated line in the release paper. The product is not in the form of a sealed package as it does not comprise a sealing cover layer on top of the construction.
The object of the invention is to provide a product in a discrete package which product is easy to handle without the user touching the adhesive of the product which will be touching the surface to which the product is applied, and at the same time this product is easier and less expensive to produce.
This object is achieved by fastening the cover layer releasably to the top layer of the package in order to make it possible to use the top layer as a non-touch grip.
A carrier layer is a coherent web which is used to move the layered product through the production process even after other layers have been cut into their final size and it reduces the cost of production when the carrier layer is made a part of the finished product instead of wasting the carrier layer totally or partly during the production process.
In order to make the process very simple, the top layer may be the carrier layer but it is also possible to use a second layer as carrier layer and, in this case, the second layer may be present between the cover layer and the top layer in the finished product. In this case the bond strength R1 between the cover layer and the second layer is smaller than the bond strength S1 between the second layer and the top layer. In fact S1 may be so large it is considered unreleasable.
It is possible to add a release layer as a separate layer and use standard material for the process; otherwise the release layer can be a release surface on the upper side of the bottom layer of the package.
In order to make the application procedure as simple as possible for the user of the product it is advantageous that:
1) the bond strength R1 between the top layer of the package or a second layer and the cover layer is higher than the bond strength R2 between the adhesive layer and the release layer, and
2) the bond strength R4 between the release layer and the bottom layer of the package is higher than the bond strength R2 between the adhesive layer and the release layer, and
3) the bond strength between the adhesive layer and the surface to which the product has been applied is higher than the bond strength R1.
When the user applies a dressing which agrees with the above demands for the bond strength between the different layers, the user first separates the top layer and the bottom layer of the package. When doing this, the release layerxe2x80x94whether this layer is a part of the bottom layer or a separate layerxe2x80x94will come off together with the bottom layer and afterwards the bottom layer and the release layer can be thrown away. This leaves the user with the top layer to which the product comprising the cover layer and an adhesive layer is attached. Now the user can use the top layer of the package to handle the product and assure the product is placed correctly. When the adhesion between the layered product and the surface to which the product is fastened is higher than the bond strength between the top layer and the cover layer, the user can remove the top layer of the package from the applicated product without problems and throw it away.